Snap acting trigger switch



Aug. 23, 1966 G. J. BURY SNAP ACTING TRIGGER SWITCH Filed June 18, 19642 Sheets-Sheet 1 INVENTOR. 06 George J Bury BY 2 2 I86 I50 46 FIGS Aug.23, 1966 G. J. BURY SNAP ACTING TRIGGER SWITCH 2 Sheets-Sheet 2 FiledJune 18, 1964 INVENTOR. George J Bury gu His 1477) United States Patent3,268,700 SNAF ACTING TRIGGER SWITCH George J. Bury, Antioch, Ill.,assignor to Illinois Tool Works Inc., Chicago, 111., a corporation ofDelaware Filed June 18, 1964, Ser. No. 376,154 7 Claims. (Cl. 200-157)This invention relates in general to a switch construction, and moreparticularly, relates to a manually actuated two pole single throwtrigger switch of the snap acting variety.

This invention is an improvement upon the switch construction shown,described and claimed in my copending application filed July 11, 1962having a Serial No. 209,197 and entitled Snap Acting Trigger Switch nowPatent No. 3,142,741.

It has long been desired to have a simple, safe, economical snap actingswitch for association with power tools and the like. Switchesassociated with electrically powered tools which have a pistol-likegrip, often are called trigger switches due to their actuation by asqueezing action on the part of the operator. In my aforementionedcopending application, I have shown and disclosed a single pole singlethrow trigger switch which is efiic-acious for its intended purpose.However, the instant device provides a double pole single throwmechanism which is operable with higher current capacities in the samesized envelope.

It is the general object of this invention to provide an economicalunitary compact snap acting trigger switch of the single throw doublepole variety for association with electrically powered tools and thelike.

It is a further object of this invention to provide a trigger switch ofthe double pole variety which eliminates complicated mechanisms, is easyto assemble per se, and, in turn, is easy to assemble on the equipmentit is designed to actuate.

It is a further object of this invention to provide a single throwdouble pole trigger switch as above set forth which has a manuallyengage-able portion made of insulating material and which iselectrical-1y isolated from the portions of the switch mechanism whichcarry electrical current in a manner to prevent any possible contact bythe operator of the switch.

While the particular structural features of the specific embodimentshown in the drawings are important, it is to be understood that theprecise features shown and described may be varied with the broaderaspects of the invention. To acquaint those skilled in the art with theform of construction of the invention, the invention will now bedescribed in connection with the accompanying drawings, in which:

FIG. 1 is a side elevational view of the switch construction with thecover removed and a portion of the trigger mechanism shown in section;

FIG. 2 is a sectional view along lines 22 of FIG. 1;

FIG. 3 is a sectional view along lines 3-3 of FIG. 1;

FIG. 4 is a perspective view of a power tool of the portable varietywhich may utilize a switch which is the subject of the instantinvention;

FIG. 5 is a view of the switch body shown in FIG. 1 without the triggerand the actuating mechanism therein;

FIG. 6 is a view of the cover for the body shown in FIG. 5;

FIG. 7 is a view along lines 7-7 of FIG. 5;

FIG. 8 is a view along lines 8-8 of FIG. 6;

FIG. 9 is a vertical elevational view of the trigger mechanism indetached relation;

FIG. 10 is a sectional view of the trigger along lines 1010 of FIG. 9;

3,268,768 Patented August 23, 1966 FIG. 11 is a plan view of the triggermechanism along lines 1111 of FIG. 12;

FIG. 12 is a side elevational view of the contact mechanism along lines1212 of FIG. 11; and

FIG. 13 is a perspective view of the terminal means and movable contactmeans in detached relation.

Many types of electrical devices, such as portable tools and the like,utilize a trigger mechanism to actuate the tool. A portable tool in theform of a drill having a trigger mechanism 22 associated therewith iselectrically actuated by conventional electrical motor power means (notshown) through electrical wire 24 associated with the usual source ofelectrical power. The switch mechanism 22 is generally associated withthe handle or button mechanism of the powered tool with only the triggerportion of the switch extending exteriorly of the casing of the tool. I

While the instant switch 22 is shown associated with a portableelectrically powered tool, su-ch as a drill, this showing is to beconsidered illustrative rather than limiting. It is, of course,contemplated that the instant switch may be associated with any otherdevices requiring a trigger electrical actuation.

The switch 22 per se comprises a chambered base por tion means 26, acover means 28, a trigger means 30, fixed terminal means 32, and movablecontact means 34. The base means 26, cover means 28, trigger means 30,and portions of the movable contact means 34 are preferably molded outof an insulating plastic material such as sold under the trade name ofLexan, nylon, or other materials having similar moldable chemicalcompositions, electrical insulating properties, and strengthcharacteristics.

The chambered base means 26 has a terminal receiving means portion 36comprising chambers 38, 40, 42, and 44 for receipt of combination fixedcontact means and quick wire attaching means. While the presentinvention is designed to provide a double insulation effect byaccommodating two input and output wire connections through adjacentchambers (38, 40 or 42, 44), it will be apparent that single input andoutput wire connections, as is conventional, are also contemplated. Thechambers are separated by somewhat Z-shaped bosses 46 and 48 on oppositesides of a central inverted T-shaped boss 50 which projects a slightlyhigher distance. A central chamber means 52 is located above theterminal area 36 for receipt of the movable contact means. Side walls 54and 56 of the base along with the cover means 28 complete the terminalchambers 38 and 44 and the contact chamber 52.

A hollowed-out portion, or notch 58 is formed in the right hand portionof chamber 52 as shown in FIGS. 1 and 5 for receipt of a cross pin 60which may be molded integral therewith or may be applied at a latterstage. The pin 60 serves as an anchor for spring 136 as shall becomeapparent.

A molded pin 62 (or an aperture for receipt of a post assembled pin) isformed in the side wall 54 for cooperation with the similar pin 62a oraperture in the cover 28.

An internal boss 64 is located at the bottom end of side surface 66 ofthe wall 56 which forms the track for the movable slide member 114 ofthe contact actuation means as shall be explained. A narrow neck portion70 separates chamber 72 from chamber 52, chamber 72 receiving the slidemember and the compression spring as shall be discussed. The chamber 72has a straight side wall 68, a lower neck portion 70, and an uppernarrowed-down neck portion 74 defined by two bosses 76 and 78. Aninternal shoulder 80 of chamber 72 receives one end of the compressionspring 134. Angularly disposed surface 82 has substantially the sameangular-ity as lug of member 114 which is movable in chamber 72.

Outer surface 84 of the base serves as a stop for inward movement of thetrigger as shall become apparent. Locating holes 86 and 88 receiveintegrally molded pins for cooperation with similarly formed apertures86a and 88a of the cover means 28. Holes 92 and 94 serve to mount theentire switch construction to the mounting lugs of the interior of theportable tool (not shown).

As best shown in FIG. 6 the cover 28 has a complementary chamber portion52a at the lower end 98 and an upper portion 96 which serves as a covermeans to chamber 72. The cover means is mounted by the aforementionedpins. Glue or suitable resins may be used to hold the cover to the baseportion if desired. Aperture 86 mounts a pivot pin 98 for the triggermechanism 30. The trigger mechanism comprises a U-shaped member having aweb portion 100 which is somewhat thickened and extending arms 102 and104. The top portion 106 is coextensive with the arms and each arm has abore 108 to receive the pin 98. A pair of oppositely disposed slots 110and 112 are slightly angularly disposed in the upper portion of armmembers 104 and 102 for receipt of extending bosses 116 and 118 ofmovable member 114.

Movable member 114 has an outwardly extending boss 120 which has asurface 122 in opposition to surface 80 of the base to trap a loadingcompression spring 134 which loads the trigger to the right as viewed inFIG. 1 and the member 114 in a downwardly direction. Member 114 isformed with an enlarged end portion which is bifurcated at 124 to formtwo arms 126 and 128 having V- shaped notches 130 and 132 adjacent theterminal edges thereof. The aperture formed at 124 is adapted to receivethe spring 136 which is mounted to fixed pin 60 on the base and to themovable contact means 138.

The movable contact means 138 comprises a plastic member 140 which isgenerally U-shaped, including a pair of arms and an interconnecting bailportion, wherein the ends of the arms have knife edges 142 and 144 whichcooperate respectively with the notches 130 and 132 of member 114.Spring 136 is connected to member 140 by an anchor means in the form ofa cross pin 146 which extends across the aperture formed by the two armsas shown in FIGS. 11 and 12. Flexible contact carrying members 148 and150 are mounted in spaced relationship to member 140 and carry thewedge-shaped contacts 152 and 154 on the bottom sides thereof forcooperation with the fixed terminal means upon actuation of member 114.

The contacts 152 and 154 may be made of silver or other appropriatematerial. The movable contact means 138 may take any of a variety offorms, although it is preferable to have the movable contacts 152 and154 not only electrically isolated relative to each other, but inaddition, to have some relative flexibility so that minute tolerancesrelative to the height of the various fixed contacts will not causearcing or degradation of the other contact connection due toinsufiicient contact pressure. The flexibility allows both contacts 152and 154 to seat firmly on the fixed contact means.

The fixed contact means and quick Wire connectors comprise four separatestampings 156, 158, 160, and 162. These are perhaps best shown in theperspective view FIG. 13. Each of the members 156-162 has a lower endportion which is angularly disposed, identified by the referencenumerals 164, 166, 168, and 170, for cooperation with the bare end of awire as shown in FIG. 1. Simple stripping of a wire and jamming it inthe respective apertures 38, 40, 42, and 44 will cause the flexible endportions 164,166, 168, and 170 to deflect upwardly and bite into thewire for a firm electrical connection thereto while preventingaccidental disengagement thereof.

Struck out tongues 172, 174, 176 and 178 of the respective membersengage the various other sides of the bosses for locating and holdingmembers 156, 158, 160, and 162 in place in their chambers. Reverselybent portion 180 and upstanding portion 182 terminates in a downturnedportion 184 on member 156 and serves as one of the four fixed contacts.The cooperating oppositely disposed contact to contact 184 is the freeend of member 160 which has a vertically extending portion 186 whichterminates in reversely extending contact portion 188. The contactportions 184 and 188 cooperate with the wedge-shaped contact 154 of themovable contact means 138.

Member 158 has a vertically extending portion 190 terminating in areversely extending contact portion 192 for cooperation with contact 152and member 162 forms the opposite contact having horizontally extendingportion 194 that cooperates with the top of boss 48 with upwardlyextending portion 196 terminating in reversely extending contact portion198 for cooperation with the 6 other side of contact 152. Due to thespringy nature of the members 156, 158, 160, and 162, and thewedge-shaped nature of the contacts 152 and 154, good contact will bemade for good electrical connection therebetween.

The operation of the device is as follows: With no pressure applied tothe trigger means 30, the actuation bar 114 is maintained in itslowermost position (shown in FIG. 1) by the compression spring 134.Pivoting lever contact carrying means 138 is maintained in its upperraised position by the relative location of the pin 60 and compressionspring 136 whereby the contacts 152 and 154 are making no contact withthe fixed contact portions 184, 188, 192, and 198. This causes an opencircuit condition to both circuits as will be apparent.

As pressure is applied to the trigger 30 (to the left as viewed in FIG.1), the trigger pivots about pin 98 causing the slots and 112 therein tomove wings 116 and 118 upwardly between the bosses 76 and 78 to thedotted line position shown in FIG. 1. As the actuating bar member 114travels upward, pivot point notches and 132 on the lower end thereofpasses over the line of action of the spring 136 causing member to snapdownwardly and the contacts 152 and 154 to engage the fixed contacts188, 184, 192, and 198.

It will be apparent that when the member 140 goes over center thecontacts move into engagement to make both circuits with a snap action.This closed circuit condition is maintained so long as pressure isapplied to the trigger. As pressure on the trigger is released, thecompression spring 134 forces member 114 downwardly again passing thepoint of the center of spring 136 causing the member 140 to return tothe position shown in FIG. 1. Any contact weld tendency caused byarcing, etc., is sheared by the twisting motion of the contacts 152 and154 as the member 144 starts its downward motion. If desired a standardtrigger lock arrangement may be employed as shown in the aforementionedapplication.

Although a specific embodiment of the invention has been shown anddescribed, it is with full awareness that many modifications thereof arepossible. The invention, therefore, is not to be restricted exceptinsofar as is necessitated by the prior art and by the spirit of theappended claims.

What is claimed as the invention is:

1. A trigger switch comprising chambered base means and cover meansassembled together to define a switch enclosure having first and secondopenings at different portions thereof, pivot means located adjacentsaid first opening, manually engageable pivotal trigger means mounted onsaid pivot means, a plurality of fixed contact means mounted in saidswitch enclosure having terminal portions adjacent said second opening,at least one of said fixed contact means being electrically isolatedfrom another fixed contact means, movable contact means comprising firstand second lever means, said first lever means being connected to saidtrigger means for reciprocatory movement responsive to pivotal movementof said trigger means, said second lever means carrying spaced contactmeans on the end thereof and being pivotally mounted on said first levermeans, spring means engaged with said second lever means and said basemeans to provide overcenter snap action movement of said second levermeans upon reciprocatory movement of said first lever means, wherebymovement of said trigger means causes movement of said first and secondlever means and movement of said movable contact means into engagementwith said fixed contact means with a snap-like action.

2. A trigger switch comprising means defining a switch enclosure means,pivot means located on said enclosure means, manually engageable pivotaltrigger means mounted on said pivot means, a plurality of spaced fixedcontact and terminal means mounted in said switch enclosure means havingterminal portion means for quick circuit connection to electrical wires,at least one of said fixed contact means portions being electricallyisolated from another fixed contact means portion, movable contact meanscomprising first and second contacts respectively engageable with saidspaced fixed contact means and operatively connected to said triggermeans for movement responsive to pivotal movement of said trigger means,spring means engaged with said movable contact means and said enclosuremeans to provide overcenter snap action movement of said movable contactmeans on movement of said trigger means, whereby movement of saidtrigger means causes movement of said first and second contacts intoengagement with said fixed contact means with a snap-like action.

3. A trigger switch comprising chambered base means and cover meansassembled together to define a switch enclosure having openings atopposite ends thereof, pivot means located adjacent said first opening,manually engageable pivotal trigger mean-s mounted on said pivot means,first, second, third, and fourth fixed contact means mounted in saidswitch enclosure each having terminal portions adjacent said secondopening, each of said fixed contact means being electrically isolatedfrom the other fixed contact means, movable contact means comprisingfifth and sixth spaced contacts and first and second lever means, saidfirst lever means being connected to said trigger means forreciprocatory movement responsive to pivotal movement of said triggermeans, said second lever means carrying said fifth and sixth spacedcontact means in electrically isolated relationship on the end thereofand being pivotally mounted on said first lever means, spring meansengaged with said second lever means and said base means to provideovercenter snap action movement of said second lever means uponreciprocatory movement of said first lever means, whereby movement ofsaid trigger means causes movement of said first and second lever meansand movement of said fifth and sixth movable contact means intoengagement with said first and third and second and fourth fixed contactmeans respectively with a snap-like action.

4. The switch set forth in claim 3 wherein said first and third contactsare spaced from each other for simultaneous engagement by said fifthcontact and said second and fourth contacts are spaced for simultaneousengagement by said sixth contact.

5. A trigger switch comprising means defining a switch enclosure means,pivot means located on said switch enclosure means, manually engageablepivotal trigger means mounted on said pivot means, a plurality of fixedcontact means mounted in said switch enclosure means with at least oneof said fixed contact means being electrically isolated from anotherfixed contact means, snap action movable contact means operablyconnected to said trigger means for movement responsive to pivotalmovement of said trigger means and including first lever means en gagedto said trigger means for reciprocal movement and second lever meanspivotally mounted on said first lever means, said second lever meanscarrying spaced contact means for engaging each of said electricallyisolated fixed contact means, an overcenter snap action spring meansconnected to said second lever means and switch enclosure means toprovide snap action movement of said second lever contact means withrespect to said electrically isolated fixed contact means.

6. The switch set forth in claim 5 wherein said plurality of fixedcontact means comprises first, second, third, and fourth contact meanseach having terminal means and each being individually mounted in spacedrelationship to each other for attachment to different electrical wiremeans, said first and third fixed contact means being characterized asbeing in spaced parallel relationship having end surfaces in angularopposed relationship to each other, said second and fourth fixed contactmeans being spaced relative to said first and third fixed contact meansand having end surfaces angularly disposed in opposed relationshiprelative to each other, and said second lever contact means comprisingfirst and second spaced wedgeshaped contact members each havingdiverging surfaces, said first and second wedge-shaped contact members'being cooperable respectively with said first and third and second andfourth fixed contact means.

7. The switch set forth in claim 5 wherein said overcenter snap actionspring means as one end thereof anchored to said switch enclosure means,said second lever means having a generally U-shaped configurationterminating in a pair of V-shaped free arm end portions and a bailportion, a pair of flexible members extending from said bail portion ofthe second lever means each mounting a contact in spaced parallelelectrically isolated relationship to one another, means intermediatesaid U- shaped arms providing an anchor for said overcenter snap actionspring means, and said first lever means having a pair of U-shaped armsadjacent one end thereof each formed with a notch cooperable with a freearm end portion of said second lever means, the space intermediate thearms of said first lever means receiving the spring means anchored tosaid second lever means, whereby movement of said first lever meansinitiates movement of said second lever means to cause movement of thecontacts on the bail portion of said second lever means with a snap-likeaction.

References Cited by the Examiner UNITED STATES PATENTS 2,336,721 12/1943Dermond 200-157 2,824,194 2/ 8 Moorhead 200166 3,121,813 2/1964 Pratt.

ROBERT K. SCHAEFER, Primary Examiner.

ROBERT S. MACON, Examiner H. HOHAUSER, Assistant Examiner.

1. A TRIGGER SWITCH COMPRISING CHAMBERED BASE MEANS AND COVER MEANSASSEMBLED TOGETHER TO DEFINE A SWITCH ENCLOSURE HAVING FIRST AND SECONDOPENINGS AT DIFFERENT PORTIONS THEREOF, PIVOT MEANS LOCATED ADJACENTSAID FIRST OPENING, MANUALLY ENGAGEABLE PIVOTAL TRIGGER MEANS MOUNTED ONSAID PIVOT MEANS, A PLURALITY OF FIXED CONTACT MEANS MOUNTED IN SAIDSWITCH ENCLOSURE HAVING TERMINAL PORTIONS ADJACENT SAID SECOND OPENING,AT LEAST ONE OF SAID FIXED CONTACT MEANS BEING ELECTRICALLY ISOLATEDFROM ANOTHER FIXED CO/NTACT MEANS, MOVABLE CONTACT MEANS COMPRISINGFIRST AND SECOND LEVER MEANS, SAID FIRST LEVER MEANS BEING CONNECTED TOSAID TRIGGER MEANS FOR RECIPROCATORY MOVEMENT RESPONSIVE TO PIVOTALMOVEMENT OF SAID TRIGGER MEANS, SAID SECOND LEVER MEANS CARRYING SPACEDCONTACT MEANS ON THE END THEREOF AND BEING PIVOTALLY MOUNTED ON SAIDFIRST LEVER MEANS, SPRING MEANS ENGAGED WITH SAID SECOND LEVER MEANS ANDSAID BASE MEANS TO PROVIDE OVERCENTER SNAP ACTION MOVEMENT OF SAIDSECOND LEVER MEANS UPON RECIPROCATORY MOVEMENT OF SAID FIRST LEVERMEANS, WHEREBY MOVEMENT OF SAID TRIGGER MEANS CAUSES MOVEMENT OF SAIDFIRST AND SECOND LEVER MEANS AND MOVEMENT OF SAID MOVABLE CONTACT MEANSINTO ENGAGEMENT WITH SAID FIXED CONTACT MEANS WITH A SNAP-LIKE ACTION.